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Taehwan Kim - One of the best experts on this subject based on the ideXlab platform.
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increased proline loading to phloem and its effects on nitrogen uptake and assimilation in water stressed white clover Trifolium repens
New Phytologist, 2009Co-Authors: Bokrye Lee, Jeanchristophe Avice, Alain Ourry, Yulan Jin, Jeanbernard Cliquet, Taehwan KimAbstract:Summary • The aim of this study was to investigate the physiological significance of increased proline loading to phloem caused by water-deficit stress in relation to nitrogen (N) uptake and assimilation. • N uptake and N assimilation were quantified by 15N tracing in well-watered (control) and water deficit-stressed white clover (Trifolium repens). De novo proline synthesis and proline loading to the phloem were also compared between treatments. The relationships among proline concentrations in phloem exudates, N uptake, and assimilation of newly absorbed N were assessed. • The newly synthesized proline in the phloem exudates increased rapidly after 3 d of water deficit. The water-deficit treatment significantly reduced the maximum nitrate reductase activity (NRA), and also attenuated de novo synthesis of amino acids and proteins in the roots. The increase in proline concentrations in phloem exudates was closely related to reductions in NRA in the roots, N uptake, and the assimilation of newly absorbed N. The accumulation of proline induced in roots by exogenous proline and NH4Cl treatments was closely associated with the decrease in NRA. • These results indicate that increased proline transport to roots via phloem caused by water deficit has a significant influence on the down-regulation of N uptake and the assimilation of newly absorbed N.
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water deficit accumulates sugars by starch degradation not by de novo synthesis in white clover leaves Trifolium repens
Physiologia Plantarum, 2008Co-Authors: Bokrye Lee, Woojin Jung, Jeanchristophe Avice, Alain Ourry, Yulan Jin, Annette Morvanbertrand, Chanwoo Park, Taehwan KimAbstract:Labeling 13CO2 in steady-state condition was used to estimate quantitative mobilization of recently fixed carbon or stored sugar during water-deficit in white clover (Trifolium repens L.). Water-deficient gradually decreased leaf-water parameters and total amount of recently fixed carbon. Amount of 13C incorporated into glucose, sucrose and soluble sugars fraction rapidly decreased after 3 days of water-deficit treatment. In contrast, the previously stored soluble sugars significantly increased after 5 days of water-deficit with a coincidence of significant decrease in starch concentration. A highly significant (P < or = 0.001) relationship between the decrease in leaf-water potential caused by water-deficit and the increase in ratio of soluble sugar/starch concentration was observed in water deficit-stressed plants. The data indicate that soluble carbohydrate accumulated by water-deficit treatment is mainly because of the hydrolysis of previously stored starch rather than to de novo synthesis.
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peroxidases and lignification in relation to the intensity of water deficit stress in white clover Trifolium repens l
Journal of Experimental Botany, 2007Co-Authors: Bokrye Lee, Kilyong Kim, Woojin Jung, Jeanchristophe Avice, Alain Ourry, Taehwan KimAbstract:To investigate the lignification process and its physiological significance under drought-stressed conditions, the changes in enzymes responsible for lignification and the related physiological parameters were determined in white clover (Trifolium repens L.) leaves during 28 d of water deficit treatment. Water deficit gradually decreased leaf water potential (Ww )t o 22.33 MPa at day 28. For the first 14 d of water deficit, ascorbate peroxidase and phenylalanine ammonialyase were highly activated. Neither a change in the parameters symptomatic of oxidative stress nor growth inhibition was observed. The reduction of leaf biomass occurred from 21 d of water deficit treatment when Ww was 22.27 MPa or less, and was concomitant with the increase of lipid peroxidation and lignin content. As Ww decreased below 21.67 MPa from 14 d of water deficit, the enhanced activation of guaiacol peroxidase, coniferyl alcohol peroxidase, syringaldazine peroxidase, and benzidine peroxidase was involved in lignification rather than in protection of plant tissues against the oxidative damage. The data indicate that a high activation of lignifying enzymes during terminal stress may be a drought stressinduced injurious symptom, which leads to reduced forage growth and digestibility.
Bokrye Lee - One of the best experts on this subject based on the ideXlab platform.
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increased proline loading to phloem and its effects on nitrogen uptake and assimilation in water stressed white clover Trifolium repens
New Phytologist, 2009Co-Authors: Bokrye Lee, Jeanchristophe Avice, Alain Ourry, Yulan Jin, Jeanbernard Cliquet, Taehwan KimAbstract:Summary • The aim of this study was to investigate the physiological significance of increased proline loading to phloem caused by water-deficit stress in relation to nitrogen (N) uptake and assimilation. • N uptake and N assimilation were quantified by 15N tracing in well-watered (control) and water deficit-stressed white clover (Trifolium repens). De novo proline synthesis and proline loading to the phloem were also compared between treatments. The relationships among proline concentrations in phloem exudates, N uptake, and assimilation of newly absorbed N were assessed. • The newly synthesized proline in the phloem exudates increased rapidly after 3 d of water deficit. The water-deficit treatment significantly reduced the maximum nitrate reductase activity (NRA), and also attenuated de novo synthesis of amino acids and proteins in the roots. The increase in proline concentrations in phloem exudates was closely related to reductions in NRA in the roots, N uptake, and the assimilation of newly absorbed N. The accumulation of proline induced in roots by exogenous proline and NH4Cl treatments was closely associated with the decrease in NRA. • These results indicate that increased proline transport to roots via phloem caused by water deficit has a significant influence on the down-regulation of N uptake and the assimilation of newly absorbed N.
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water deficit accumulates sugars by starch degradation not by de novo synthesis in white clover leaves Trifolium repens
Physiologia Plantarum, 2008Co-Authors: Bokrye Lee, Woojin Jung, Jeanchristophe Avice, Alain Ourry, Yulan Jin, Annette Morvanbertrand, Chanwoo Park, Taehwan KimAbstract:Labeling 13CO2 in steady-state condition was used to estimate quantitative mobilization of recently fixed carbon or stored sugar during water-deficit in white clover (Trifolium repens L.). Water-deficient gradually decreased leaf-water parameters and total amount of recently fixed carbon. Amount of 13C incorporated into glucose, sucrose and soluble sugars fraction rapidly decreased after 3 days of water-deficit treatment. In contrast, the previously stored soluble sugars significantly increased after 5 days of water-deficit with a coincidence of significant decrease in starch concentration. A highly significant (P < or = 0.001) relationship between the decrease in leaf-water potential caused by water-deficit and the increase in ratio of soluble sugar/starch concentration was observed in water deficit-stressed plants. The data indicate that soluble carbohydrate accumulated by water-deficit treatment is mainly because of the hydrolysis of previously stored starch rather than to de novo synthesis.
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peroxidases and lignification in relation to the intensity of water deficit stress in white clover Trifolium repens l
Journal of Experimental Botany, 2007Co-Authors: Bokrye Lee, Kilyong Kim, Woojin Jung, Jeanchristophe Avice, Alain Ourry, Taehwan KimAbstract:To investigate the lignification process and its physiological significance under drought-stressed conditions, the changes in enzymes responsible for lignification and the related physiological parameters were determined in white clover (Trifolium repens L.) leaves during 28 d of water deficit treatment. Water deficit gradually decreased leaf water potential (Ww )t o 22.33 MPa at day 28. For the first 14 d of water deficit, ascorbate peroxidase and phenylalanine ammonialyase were highly activated. Neither a change in the parameters symptomatic of oxidative stress nor growth inhibition was observed. The reduction of leaf biomass occurred from 21 d of water deficit treatment when Ww was 22.27 MPa or less, and was concomitant with the increase of lipid peroxidation and lignin content. As Ww decreased below 21.67 MPa from 14 d of water deficit, the enhanced activation of guaiacol peroxidase, coniferyl alcohol peroxidase, syringaldazine peroxidase, and benzidine peroxidase was involved in lignification rather than in protection of plant tissues against the oxidative damage. The data indicate that a high activation of lignifying enzymes during terminal stress may be a drought stressinduced injurious symptom, which leads to reduced forage growth and digestibility.
Vit Latzel - One of the best experts on this subject based on the ideXlab platform.
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transgenerational effects and epigenetic memory in the clonal plant Trifolium repens
Frontiers in Plant Science, 2018Co-Authors: Alejandra Pilar Rendina Gonzalez, Veronica Preite, Koen J F Verhoeven, Vit LatzelAbstract:Transgenerational effects can modify phenotypes of offspring generations playing thus a potentially important role in ecology and evolution of many plant species. These effects have been studied mostly across generations of sexually reproducing species. A substantial proportion of plant species are however reproducing asexually, for instance via clonal growth. Transgenerational effects are thought to be enabled by heritable epigenetic modification of DNA, although unambiguous evidence is still scarce. On the clonal herb white clover (Trifolium repens), we tested the generality of clonal transgenerational effects across five genotypes and five parental environments including soil contamination and above-ground competition. Moreover, by genome wide-methylation variation analysis we explored the role of drought, one of the parental environments that triggered the strongest transgenerational effects. We tested the induction of epigenetic changes in offspring generations using several intensities and durations of drought stress. We found that transgenerational effects of different environments were highly genotype specific and all tested environments triggered transgenerational effects at least in some genotypes. In addition, parental drought stresses triggered epigenetic change in T. repens and most of the induced epigenetic change was maintained across several clonal offspring generations. We conclude that transgenerational effects are common and genotype specific in clonal plant T. repens and potentially under epigenetic control.
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The role of transgenerational effects in adaptation of clonal offspring of white clover (Trifolium repens) to drought and herbivory
Evolutionary Ecology, 2017Co-Authors: Alejandra Pilar Rendina Gonzalez, Veronika Dumalasova, Jonathan Rosenthal, Jiří Skuhrovec, Vit LatzelAbstract:Environmentally induced transgenerational effects can increase success of offspring and thereby be adaptive if offspring experience conditions similar to the parental environment. The ecological and evolutionary significance of these effects in plants have been considered overwhelmingly in the context of sexual generations. We investigated whether drought stress and jasmonic acid, a key hormone involved in induction of plant defenses against herbivores, applied in the parental generation, trigger transgenerational effects in clonal offspring of Trifolium repens and whether these effects are adaptive. We found that drought stress experienced by parents significantly affected phenotypes of offspring ramets. Offspring ramets were bigger if they were produced in the parental water regime (control/drought). Repeated application of jasmonic acid to parents increased the subsequent growth of offspring ramets produced by stolons after they were disconnected from the parental clone. However, these offspring ramets experienced similar herbivory by the generalist Spodoptera littoralis caterpillar as did control offspring ramets, indicating that this jasmonic acid application in the parental generation did not result in a transgenerational effect comprising increased herbivory resistance. We conclude that, overall, environmental interaction in the parental generation can trigger transgenerational effects in clonal plants and some of these effects can be adaptive. Moreover, transgenerational effects in clonal plants that significantly influence their growth and behavior can ultimately affect the evolutionary trajectories of clonal populations.
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stress induced memory alters growth of clonal offspring of white clover Trifolium repens
American Journal of Botany, 2016Co-Authors: Alejandra Pilar Rendina Gonzalez, Jindřich Chrtek, Petre I Dobrev, Veronika Dumalasova, Judith Fehrer, Patrik Mraz, Vit LatzelAbstract:PREMISE OF THE STUDY The phenotype of an individual can be modified by the environment experienced by its predecessors, a phenomenon called transgenerational or maternal effects. These effects are studied mostly across sexual generations and are thought to be mediated also by epigenetic variation. However, we do not know how important transgenerational effects are across asexual generations of clonal plants. METHODS We investigated the role of different drought intensities and durations experienced by parental plants of Trifolium repens on the growth of offspring ramets after transplantation of clonal cuttings to control conditions. We also treated half of the plants with 5-azacytidine, which is a demethylating agent, to test the potential role of DNA methylation on transgenerational effects. KEY RESULTS Transgenerational effects were manifested as increased biomass of offspring ramets if parental plants experienced medium drought applied for a short period and decreased biomass of offspring ramets if parental plants experienced intense drought for a short period. These transgenerational effects were not observed for offspring of parents from the same treatments if these were treated with 5-azacytidine, whose application significantly decreased the amount of 5-methyl-2'-deoxycytidine in plants. CONCLUSIONS Transgenerational effects might play an important role in the clonal plant Trifolium repens and are probably mediated by epigenetic variation. The growth and behavior of clonal plants might be affected not only by the ambient environment but also by environments that are no longer present at the time of clonal reproduction. This phenomenon can have yet unacknowledged ecological and evolutionary implications for clonal plants.
Jeanchristophe Avice - One of the best experts on this subject based on the ideXlab platform.
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how does sulphur availability modify n acquisition of white clover Trifolium repens l
Journal of Experimental Botany, 2010Co-Authors: Sebastien Varin, Jeanchristophe Avice, Jeanbernard Cliquet, Emmanuelle Personeni, Servane LemauviellavenantAbstract:The role of S in legume growth, N uptake, and N2 fixation was investigated using white clover (Trifolium repens L.) as a model species. We examined whether the effect of sulphate addition on N fixation resulted from a stimulation of host plant growth, a specific effect of S on nodulation, or a specific effect of S on nodule metabolism. Clones of white clover, inoculated with Rhizobium leguminosarum, were grown for 140 d in a hydroponic system with three levels of sulphate concentration (0 mM, 0.095 mM, and 0.380 mM). Nodule morphological and biochemical traits, such as root length, nodule biomass and volume, nodule protein contents (nitrogenase and leghaemoglobin obtained by an immunological approach), and root amino acid concentrations, were used to analyse the effect of sulphate availability on N2 fixation. The application of sulphate increased whole plant dry mass, root length, and nodule biomass, expressed on a root-length basis. N uptake proved less sensitive than N2 fixation to the effects of S-deficiency, and decreased as a consequence of the lower root length observed in S-deficient plants. N2 fixation was drastically reduced in S-deficient plants as a consequence of a low nodule development, but also due to low nitrogenase and leghaemoglobin production. This effect is likely to be due to down-regulation by a N-feedback mechanism, as, under severe S-deficiency, the high concentration of whole plant N and the accumulation of N-rich amino acids (such as asparagine) indicated that the assimilation of N exceeded the amount required for plant growth.
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increased proline loading to phloem and its effects on nitrogen uptake and assimilation in water stressed white clover Trifolium repens
New Phytologist, 2009Co-Authors: Bokrye Lee, Jeanchristophe Avice, Alain Ourry, Yulan Jin, Jeanbernard Cliquet, Taehwan KimAbstract:Summary • The aim of this study was to investigate the physiological significance of increased proline loading to phloem caused by water-deficit stress in relation to nitrogen (N) uptake and assimilation. • N uptake and N assimilation were quantified by 15N tracing in well-watered (control) and water deficit-stressed white clover (Trifolium repens). De novo proline synthesis and proline loading to the phloem were also compared between treatments. The relationships among proline concentrations in phloem exudates, N uptake, and assimilation of newly absorbed N were assessed. • The newly synthesized proline in the phloem exudates increased rapidly after 3 d of water deficit. The water-deficit treatment significantly reduced the maximum nitrate reductase activity (NRA), and also attenuated de novo synthesis of amino acids and proteins in the roots. The increase in proline concentrations in phloem exudates was closely related to reductions in NRA in the roots, N uptake, and the assimilation of newly absorbed N. The accumulation of proline induced in roots by exogenous proline and NH4Cl treatments was closely associated with the decrease in NRA. • These results indicate that increased proline transport to roots via phloem caused by water deficit has a significant influence on the down-regulation of N uptake and the assimilation of newly absorbed N.
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water deficit accumulates sugars by starch degradation not by de novo synthesis in white clover leaves Trifolium repens
Physiologia Plantarum, 2008Co-Authors: Bokrye Lee, Woojin Jung, Jeanchristophe Avice, Alain Ourry, Yulan Jin, Annette Morvanbertrand, Chanwoo Park, Taehwan KimAbstract:Labeling 13CO2 in steady-state condition was used to estimate quantitative mobilization of recently fixed carbon or stored sugar during water-deficit in white clover (Trifolium repens L.). Water-deficient gradually decreased leaf-water parameters and total amount of recently fixed carbon. Amount of 13C incorporated into glucose, sucrose and soluble sugars fraction rapidly decreased after 3 days of water-deficit treatment. In contrast, the previously stored soluble sugars significantly increased after 5 days of water-deficit with a coincidence of significant decrease in starch concentration. A highly significant (P < or = 0.001) relationship between the decrease in leaf-water potential caused by water-deficit and the increase in ratio of soluble sugar/starch concentration was observed in water deficit-stressed plants. The data indicate that soluble carbohydrate accumulated by water-deficit treatment is mainly because of the hydrolysis of previously stored starch rather than to de novo synthesis.
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peroxidases and lignification in relation to the intensity of water deficit stress in white clover Trifolium repens l
Journal of Experimental Botany, 2007Co-Authors: Bokrye Lee, Kilyong Kim, Woojin Jung, Jeanchristophe Avice, Alain Ourry, Taehwan KimAbstract:To investigate the lignification process and its physiological significance under drought-stressed conditions, the changes in enzymes responsible for lignification and the related physiological parameters were determined in white clover (Trifolium repens L.) leaves during 28 d of water deficit treatment. Water deficit gradually decreased leaf water potential (Ww )t o 22.33 MPa at day 28. For the first 14 d of water deficit, ascorbate peroxidase and phenylalanine ammonialyase were highly activated. Neither a change in the parameters symptomatic of oxidative stress nor growth inhibition was observed. The reduction of leaf biomass occurred from 21 d of water deficit treatment when Ww was 22.27 MPa or less, and was concomitant with the increase of lipid peroxidation and lignin content. As Ww decreased below 21.67 MPa from 14 d of water deficit, the enhanced activation of guaiacol peroxidase, coniferyl alcohol peroxidase, syringaldazine peroxidase, and benzidine peroxidase was involved in lignification rather than in protection of plant tissues against the oxidative damage. The data indicate that a high activation of lignifying enzymes during terminal stress may be a drought stressinduced injurious symptom, which leads to reduced forage growth and digestibility.
Alain Ourry - One of the best experts on this subject based on the ideXlab platform.
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increased proline loading to phloem and its effects on nitrogen uptake and assimilation in water stressed white clover Trifolium repens
New Phytologist, 2009Co-Authors: Bokrye Lee, Jeanchristophe Avice, Alain Ourry, Yulan Jin, Jeanbernard Cliquet, Taehwan KimAbstract:Summary • The aim of this study was to investigate the physiological significance of increased proline loading to phloem caused by water-deficit stress in relation to nitrogen (N) uptake and assimilation. • N uptake and N assimilation were quantified by 15N tracing in well-watered (control) and water deficit-stressed white clover (Trifolium repens). De novo proline synthesis and proline loading to the phloem were also compared between treatments. The relationships among proline concentrations in phloem exudates, N uptake, and assimilation of newly absorbed N were assessed. • The newly synthesized proline in the phloem exudates increased rapidly after 3 d of water deficit. The water-deficit treatment significantly reduced the maximum nitrate reductase activity (NRA), and also attenuated de novo synthesis of amino acids and proteins in the roots. The increase in proline concentrations in phloem exudates was closely related to reductions in NRA in the roots, N uptake, and the assimilation of newly absorbed N. The accumulation of proline induced in roots by exogenous proline and NH4Cl treatments was closely associated with the decrease in NRA. • These results indicate that increased proline transport to roots via phloem caused by water deficit has a significant influence on the down-regulation of N uptake and the assimilation of newly absorbed N.
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water deficit accumulates sugars by starch degradation not by de novo synthesis in white clover leaves Trifolium repens
Physiologia Plantarum, 2008Co-Authors: Bokrye Lee, Woojin Jung, Jeanchristophe Avice, Alain Ourry, Yulan Jin, Annette Morvanbertrand, Chanwoo Park, Taehwan KimAbstract:Labeling 13CO2 in steady-state condition was used to estimate quantitative mobilization of recently fixed carbon or stored sugar during water-deficit in white clover (Trifolium repens L.). Water-deficient gradually decreased leaf-water parameters and total amount of recently fixed carbon. Amount of 13C incorporated into glucose, sucrose and soluble sugars fraction rapidly decreased after 3 days of water-deficit treatment. In contrast, the previously stored soluble sugars significantly increased after 5 days of water-deficit with a coincidence of significant decrease in starch concentration. A highly significant (P < or = 0.001) relationship between the decrease in leaf-water potential caused by water-deficit and the increase in ratio of soluble sugar/starch concentration was observed in water deficit-stressed plants. The data indicate that soluble carbohydrate accumulated by water-deficit treatment is mainly because of the hydrolysis of previously stored starch rather than to de novo synthesis.
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peroxidases and lignification in relation to the intensity of water deficit stress in white clover Trifolium repens l
Journal of Experimental Botany, 2007Co-Authors: Bokrye Lee, Kilyong Kim, Woojin Jung, Jeanchristophe Avice, Alain Ourry, Taehwan KimAbstract:To investigate the lignification process and its physiological significance under drought-stressed conditions, the changes in enzymes responsible for lignification and the related physiological parameters were determined in white clover (Trifolium repens L.) leaves during 28 d of water deficit treatment. Water deficit gradually decreased leaf water potential (Ww )t o 22.33 MPa at day 28. For the first 14 d of water deficit, ascorbate peroxidase and phenylalanine ammonialyase were highly activated. Neither a change in the parameters symptomatic of oxidative stress nor growth inhibition was observed. The reduction of leaf biomass occurred from 21 d of water deficit treatment when Ww was 22.27 MPa or less, and was concomitant with the increase of lipid peroxidation and lignin content. As Ww decreased below 21.67 MPa from 14 d of water deficit, the enhanced activation of guaiacol peroxidase, coniferyl alcohol peroxidase, syringaldazine peroxidase, and benzidine peroxidase was involved in lignification rather than in protection of plant tissues against the oxidative damage. The data indicate that a high activation of lignifying enzymes during terminal stress may be a drought stressinduced injurious symptom, which leads to reduced forage growth and digestibility.
